DIY Slide Scanner Scanning via DSLR

UPDATE: The approximate location for the slide holder mentioned in the video is to determine where the slide holder platform will go, then the exact location for the holder itself needs to be determined before it is attached to the platform (I used two small screws in the channel). Since making the video I've attached a diffuser at the end to mitigate unevenness in sky light. I used two pieces of translucent plastic cut from a small storage box and put a sheet of tissue paper between them. The resulting slower shutter speeds are not a problem since everything is held firmly in place.